Department of Community Development
Reference: Intergovernmental Agreement (IGA) between the City of Brighton and City of Thornton
To: Mayor Gregory Mills and Members of City Council
Through: Michael P. Martinez, City Manager
Prepared By: Kim Bauer, Associate Planner
Date Prepared: September 17, 2026
PURPOSE
The purpose of this study session is to provide City Council with an overview of the previous Intergovernmental Agreements (IGAs) between the City of Brighton and the City of Thornton regarding the management of growth boundaries, which are now expired. As such, staff has been working with the City of Thornton on drafting a new IGA. The following background section outlines the proposed changes and revisions to facilitate Council feedback and confirm that the proposed direction aligns with Council’s expectations.
BACKGROUND
Brighton and Thornton share a common growth area and both cities agreed to adopt an Intergovernmental Agreement (IGA) in 2001 to address shared growth issues and establish a growth boundary. That IGA was originally set to expire on January 1, 2010, but was extended three times, ultimately expiring on April 30, 2012. On August 21, 2012, City Council approved an updated IGA that expired on December 31, 2022.
The previous IGA therefore has lapsed, but both parties are interested and eager to re-establish the growth boundary IGA.
The previous IGA has served both communities well, however, staff has started to develop an updated IGA, working with the City of Thornton, that will reflect new goals and circumstances. The proposed IGA includes several revisions intended to simplify the document, update references, and reflect current planning conditions that have changed since the adoption of the 2012 agreement.
While the overall purpose of the agreement remains largely the same, the proposed revisions are intended to improve clarity and remove provisions that are no longer applicable. The key revisions are outlined below with additional con...
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